/in/foo.c: In function 'main':
/in/foo.c:6:22: error: 'xmax' undeclared (first use in this function)
  scanf("%d%d",&xmin,&xmax);
                      ^~~~
/in/foo.c:6:22: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:5:11: warning: unused variable 'max' [-Wunused-variable]
  int xmin,max;
           ^~~